The quality control manager at a compact fluorescent light bulb CFL factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7 467 hours The population standard deviation is 900 hours A random sample of 81 light bulbs indicates a sample mean life of 7 217 hours a At the 0 05 level of significance is there evidence that the mean life is different from 7 467 hours b Compute the p value and interpret its meaning c Construct a 95 confidence interval estimate of the population mean life of the light bulbs d Compare the results of a and c What conclusions do you reach a Let u be the population mean Determine the null hypothesis Ho and the alternative hypothesis H Ho H